Circuit interrupter



2 Sheets-Sheet 1 Filed July 15, 1950 Fig.2.

Fig.|.

- INVENTORS Benjamin H Baker 8: Winthrop M. Leeds.

WITNESSES:

Nov. 2, 1954 a. P. BAKER ETAL 2,693,519

CIRCUIT INTERRUPTER Filed July 15, 1950 2 Sheets-Sheet 2 Fig. 5.

I WITNESSES: I INVENTORS a Wk 0 Q Benjamin P. Baker 8 Winthrop M. Leeds.

% ATTORN United States Patent D crncurr uvrnnnurrnu Benjamin P. Baker, Turtle Creek, and Winthrop M. Leeds, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application July 15, 1950, Serial No. 174,107

20 Claims. (Cl. 200150) This invention relates to circuit interrupters in general, and more particularly to circuit interrupter tank configurations, and to circuit interrupter mounting arrangements.

In United States patent application Serial No. 624,284, filed October 24, 1945, now U. S. Patent 2,581,571, issued January 8, 1952, to Benjamin P. Baker and Oswald von Mehren, and assigned to the assignee of the instant application, there is disclosed and claimed features of a spherical tank construction utilized in a compressed gas circuit interrupter. A general object of our invention is to provide an improved circuit interrupter, such that the tank will have advantages over the tank construction disclosed in the aforesaid patent, by having a minimum fiuid volume, minimum electrical clearances, and yet will be mechanically strong and economical to fabricate.

Another object is to provide an improved tank configuration, particularly suitable for liquid type breakers, in which the electrical clearances between the interrupting units and the grounded tank walls will be adequate, and yet the liquid volume enclosed by the tank will be a minimum. By having less liquid volume, the cost of the liquid within the breaker will be reduced. and the cost of handling and periodically filtering the liquid will be diminished.

Still a further object is to provide an improved tank configuration utilizing in the fabrication thereof easily workable and commercially obtainable parts.

Another object is to provide an improved circuit interrupter with improved means for mounting the terminal bushings.

Further objects and advantages will readilv become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

Figure l is a side-elevational view, partially in vertical section, of an improved tank construction embodying our invention, the arc-extinguishing units being shown in the closed circuit position;

Fig. 2 is an end elevational view, partially in vertical section, of the interrupter illustrated in Fig. 1;

Figs. 35 are views, in section, taken along the lines IlI-TTI, lV-IV and VV of Fig. 1, looking in the direction of the arrows; and

Fig. 6 is an enlarged fra mentary sectional view taken along the line VI-VI of Fig. 1, looking in the direction of the arrows.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference character 1 generally designates a circuit interrupter, particularly one of the liquid break type. including a pair of terminal bushings 2, 3 extending interiorly within a tank structure 4.

Depending from the lower ends of the terminal bushings 2, 3 are a pair of identical arc-extinguishing units. generall designated by the reference numeral 6. and electrically interconnected, in the closed circuit position shown in Fitz. l, by a conducting bridging member 7, actuated vertically, in a reciprocal manner, by an insulatinz lift rod 8. The lift rod 8 is actuated by a leverage mechanism 5, driven by a horizontally reci rocally movable pull rod 19. The null rod 19 is shielded by a tube 20. more clearly shown in Fig. 2.

The end of the pull rod 19 is bifurcated. as at 21, and is pivotally connected to the crank arm 22 integrally formed with an operating shaft 23 (Fig. 6). Rotatable with the shaft 23 is a plate 24, to which is welded a toggle link 25. A knee-pin 26 pivotally interconnects the toggle link 25 with a cooperating toggle link 27. A

2,693,519 Patented Nov. 2, 1954 spring seat 28 is fixed, as by welding, to the toggle link 27. A compression spring 29 surrounds the toggle link 27, being interposed between the spring seat 28 and an apertured spring seat 30. The spring seat 30 is stationarily pivotally mounted between a pair of support plates 31, 32, the latter being fixed, as by welding, to a head 17 of the interrupter 1. The support plates 31, 32 also serve to journal the operating shaft 23.

The upper end of the toggle link 25 is pivotally connected, as at 33, to a link 34, the lower end of which is pivotally connected, as at 35, to a lever 36, the lower end of which is stationarily pivoted on a pin 37 extending between the two support plates 31, 32.

The upper end of the lever 36 is pivotally connected, as at 38, to a triangularly-shaped actuating plate 39. A moving pivot 40 interconnects the insulating lift rod 8 with the actuating plate 39, suitable guide means, not shown, being utilized to assist in guiding the vertical reci rocal motion of the lift rod 8.

The actuating plate 39 is also pivotally connected, as at 41, to a lever 42, the upper end of which is stationarily pivotally mounted, as at 43, between the two support plates 31, 32.

The operation of the leverage mechanism 5 will now be described. To effect an opening operation of the interrupter, from the closed circuit position thereof, as shown in Figs. 1 and 2, the pull rod 19 is moved toward the right, as viewed in Fig. 2, by any suitable mechanism, which forms no part of our invention. The rightward movement of the pull rod 19. as viewed in Fig. 2, effects clockwise rotative motion of the operating shaft 23, which breaks the toggle 44, comprising the two toggle links 25, 27, being assisted by the spring force 29. The breaking of the toggle 44 f rces link 34 diagonally downwardly to rotate the lever 36 in a clockwise direction about the stationary pivot 37 to effect counterclockwise rotation of the triangularly-shaped actuating plate 39, to thereby cause downward opening motion of the insulating lift rod 8. The lever 42 swings slightly upwardly in a counterclockwise direction about the stationary pivot 43 during this opening motion.

The downward opening motion of the lift rod 8 correspondingly effects downward opening motion of the conducting bridging member 7 to thereby effect opening of the contact structure within the units 6 to effect breaking of the circuit therein. Continued downward movement of the lift rod 8 and the conducting bridge 7 effects two isolating gaps in the circuit, as well known by those skilled in the art.

For a description of the manner of the interrupting of the arcs within the units 6, reference may be had to U. S. Patent 2,462,733, issued February 22, 1949, to Gilbert 1. Easlev. entitled Circuit Interrunter, and assigned to the assignee of the instant application. This patent, in Fig. 2 thereof, shows the general arrangement of the sequential contact construction which may be utilized in the arc-extinguishing units 6, but which forms no part of our invention, and consequently is not described.

Our invention is, in part, particularly concerned with the configuration or shape of the tank 4. As shown more clearly in Figs. 1 and 2, it will be noted that the body portion of the tank 4 is preferably formed from a pair of circular semi-elliptical or oval-shaped dished heads 9, 10 welded along the seam 11. The resulting construction is such that sections taken therethrough, as indicated by Figs. 4 and 5, are of elliptic or oval shape. Such a construction gives a minimum liquid volume, which reduces the initial and maintenance costs of the breaker, and yet lends itself readily to having great mechanical strength. Moreover, it will be observed that the electrical clearances interiorly of the tank 4, between the live parts of the units 6 and the interior walls of the grounded tank 4 are adequate.

To support the terminal bushings 2 and 3 within the tank 4, we weld an upstanding elliptically or oval-shaped cylinder, or extension 12 to a cut-out portion 13 of the body portion of the tank 4. Preferably the upper end of the cylinder 12 has a flange 14, which cooperates with a flange 15 provided at the lower end of a sub-assembly 16 including the terminal bushings 2, 3 and the metallic third head 17. The cylinder 12 and head 17 collectively constitutea housing means disposed at the top of the body portion of the tank 4 and serve to support the two terminal bushings 2, 3.

Thus, the tank 4 includes a lower portion, below the plane A, which may be designated by the reference character 4a, and an upper extended portion above the plane A which may be designated by the reference character 4b. The extension 412, including the oval cylindrical part 12, carries the bushings 2, 3 and permits the use of longer bushings for higher-voltage service without increasing the size or volume of the lower portion 4a'of the tank, it being noted that the bushings have a length X which, as seen in Fig. 1, is greater than twice the radius R'of the lower portion 4a of the tank 4.

Preferably the terminal bushings 2, 3 are of the condenser type so that the operating mechanism 5, being adjacent the mid-portion of the terminal bushings 2, 3, is only adjacent surfaces which are at substantially ground potential.

It will. be observed that horizontal sections taken through the tank 4 on the planes B, C, D or E are of oval configuration. Also the cylindrical member 12, being of oval or elliptical shape, is long in one horizontal direction, that isthe direction from right toleft in the plane of the showing of Fig. l, to accommodate the terminal bushings 2, 3, with a space 45 therebetween to accommodate the leverage mechanism 5. The crosssection through the cylindrical member 12 is narrow in In assembling the interrupter, the two terminal bush ings 2 and 3 are secured to the head 17, and then the arc extinguishing units 6 are threadedly secured and clamped into place at the lower ends of the bushings 2, 3. The sub-assembly 16 is then lowered into the tank 4, so that the flanges 14, 15 may be rigidly held together by suitable nuts and bolts, not shown.

It will be noted that the configuration of the tank 4 with respect to the interrupting units 6 is such that substantially all of the surface elements of the tank 4 are spaced the minimum distance away from the 'units 6.to prevent flash-over therebetween. In other words, considering the distance S in Fig. 4 as the minimum disance which will prevent flash-over between the live parts of the units 6 and the interior surface of the grounded tank 4, it will be noted that the distance S is substantially preserved between the units 6 and the interior walls of the grounded tank 4. Thus, the envelope of the-tank 4 is such as to provide only enough clearance between the interior walls of said tank 4 and the units 6 to prevent breakdown for the voltage considered, The result of such a construction is that the volume enclosed by the tank 4 is a minimum, and yet the surface elements of the tank or envelope 4 are spaced only the minimum distance from the units 6 and the conducting bridging member 7 to prevent flash-over therebetween.

From the foregoing description'of our invention, it will be apparent that we have provided an improved tank'configuration particularly adapted for liquid-break types of circuit interrupters. However, if desired, the construction could be utilized in a compressed air interrupter having the tank 4 pressurized, as disclosed in the aforesaid United States patent.

It will be observed that the tank 4 is simple and economical to fabricate. It will moreover be noted that the circular semi-elliptical or oval-dished heads 9, 10 are readily available commercially. The resulting structure is strong, and utilizes a minimum volume of liquid or other fluid.

Although wehave shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the appended claims.

We claim as our invention:

l. A circuit interrupter construction having two circular substantially semi-elliptical dished heads secured together by a substantially vertical single seam to form a tank, and a pair of terminal bushings extending within the tank at the upper end thereof.

2. A circuit interrupter tank of generally circular side elevational shape, horizontal sections through which are of substantially elliptic configuration with rounded ends, and at least one arc-extinguishing unit disposed therewithin.

3. A circuit interrupter construction having two dished heads secured together by a substantially vertical single seam, an upstanding oval cylindrical member at the top thereof, and a pair of terminal bushings extending through the oval cylindrical member.

4. A circuit interrupter construction having two sub stantially semi-elliptical dished heads secured together by a single seam, an upstanding oval cylindrical member thereon, a third head, a pair of terminal bushings secured to the third head, and the third head being socured to the outer end of the oval cylindrical member.

5. A circuit interrupter including a fixed tank of constant volume, means supporting the fixed tank adjacent the lower end thereof, twoterminal bushings extending into the tank adjacent the upper end thereof, said tank having its lower half generally semi-circular in cross section taken in a vertical plane extending through the tank and through the two terminal bushings, horizontal sections taken through the lower half of the tank being of oval shape with rounded ends, said tank having extended housing means at its upper end for receiving the two terminal bushings, and the cross-sectional area of said extended housing means taken on a horizontal plane being smaller than the cross-sectional area through the mid-portion of the tank taken on a horizontal plane.

6. A circuit interrupter including a fixed tank of con-' stant volume, means supporting the fixed tank adjacent the lower end thereof, two terminal bushings extending into the tank adjacent the upper end thereof and having their lower interior ends extending adjacent the mid-portion of the tank, said tank having its lower half generally semi-circular in cross section taken in a vertical plane extending through the tank and through the two terminal bushings, arc extinguishing units supported at the interior ends of the terminal bushings adjacent the portion of the tank of greatest cross-section area taken on a horizontal plane, horizontal sections taken through the lower half of said tank being of oval configuration.

with rounded ends, said tank having an extended portion at its upper end for recelving the two terminal bushings, the cross-sectional area of said extended portion. taken on a horizontal plane being smaller than the cross-- nal bushings, being at these points only slightly wider than the terminal bushings.

7. A circuit interrupter including a fixed tank of constant volume, means supporting the fixed tank adjacent the lower end thereof, two terminal bushings extending into the tank adjacent the upper end thereof, said tank having its lower half generally semi-circular in cross section taken in a vertical plane extending through the tank and through the two terminal bushings, horizontal sections taken through the lower half of said tank being of oval configuration with rounded ends, said tank having an'extended' portion at its upper end for receiving the two terminal bushings, the cross-sectional area of said extended portion taken on a horizontal plane being smaller than the cross-sectional area through the mid-portion of the tank taken on a horizontal plane, and the radius of the semi-circular lower portion of the tank being less than half the length of the terminal bushings.

8. A circuit interrupter including a fixed tank of constant volume, means supporting the fixed tankadjacent the lower end thereof, two terminal bushings extending into the tank adjacent the upper end thereof and having their lower interior ends extending adjacent the midportion of the tank, said tank having its lower half generally semi-circular in cross section taken in a vertical plane extending through the tank and through the two terminal bushings, arc extinguishing units supported at the interior ends of the terminal bushings adjacent the portion of the tank of greatest cross-sectional area taken on a horizontal plane, horizontal sections taken through the lower half of the tank being of oval configuration with rounded ends, said tank having an extended portion at its upper end for receiving the two terminal bushings, an operating mechanism, the cross-sectional area of said extended portion taken on a horizontal plane being smaller than the cross-sectional area through the mid-portion of the tank taken on a horizontal plane, said extension at the top portion of the tank having a cross section which is long in one horizontal direction to receive the two terminal bushings with a space therebetween for the operating mechanism and which is narrow in the other horizontal direction adjacent the two terminal bushings, being at these points only slightly wider than the terminal bushings, and the radius of the semi-circular lower portion of the tank being less than half the length of the terminal bushings.

9. A circuit interrupter tank construction resulting from securing two circular dished heads together by a single seam, horizontal sections through which are of oval configuration with rounded ends, and a pair of terminal bushings extending within the tank.

10. A circuit interrupter tank of circular side elevational shape, horizontal sections through which are of oval configuration with rounded ends, and at least one arc-extinguishing unit disposed therewithin.

11. A circuit interrupter tank construction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration with rounded ends, an upstanding cylindrical member, and a pair of terminal bushings extending through the cylindrical member.

12. A circuit interrupter tank construction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration with rounded ends, an upstanding cylindrical member, horizontal sections through which are also of oval configuration, and a pair of terminal bushings extending through and being supported by the cylindrical member.

13. A circuit interrupter tank constriction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration with rounded ends, an upstanding cylindrical member, horizontal sections through which are also of oval configuration, a third head, a pair of terminal bushings secured to the third head, and the third head being secured to the outer end of the cylindrical member.

14. A circuit interrupter tank construction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration, a pair of terminal bushings extending within the tank, and the radius of the lower half of the tank taken in a vertical plane extending through the tank and also through the terminal bushings being less than half the length of the terminal bushings.

15. A circuit interrupter tank construction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration, upstanding housing means at the top of said dished heads, a pair of terminal bushings extending through the upstanding housing means, and the radius of the lower half of the tank taken in a vertical plane extending through the tank and through the two terminal bushings being less than half the length of the terminal bushings.

16. A circuit interrupter tank construction resulting from securing two dished heads together by a single seam, horizontal sections through which are of oval configuration, an upstanding cylindrical member, horizontal sections through which are also of oval configuration, a

8 pair of terminal bushings extending through the cylindrical member and having their lower ends disposed adjacent the mid-portion of the tank, an operating mechanism, and a space within the cylindrical member between the two terminal bushings for accommodating the operating mechanism.

17. A circuit interrupter including a tank, a pair of terminal bushings extending into the tank adjacent the upper portion thereof, means mounting the tank adjacent the lower end thereof, the body portion of the tank being generally circular when viewed in side elevation, a cylindrical portion extending generally upwardly from the circular body portion to support at least one terminal bushing adjacent the mid-portion thereof, and horizontal sections taken through the body portion of the tank being generally elliptical with rounded ends.

18. The combination in a liquid-break circuit interrupter of a tank having a body portion of generally circular shape when viewed in side elevation, a pair of terminal bushings converging inwardly and extending into the body portion of the tank from the uper end thereof, housing means extending upwardly from the body portion of the tank to support the terminal bushings adjacent the mid-portion thereof, and horizontal sections taken through the body portion of the tank being generally elliptical with rounded ends.

19. A circuit interrupter including a tank, a pair of terminal bushings extending into the tank adjacent the upper portion thereof, means mounting the tank adjacent the lower end thereof, the body portion of the tank being generally circular when viewed in side elevation, housing means extending generally upwardly from the circular body portion to support the terminal bushings adjacent the mid-portion thereof, horizontal sections taken through the body portion of the tank being generally elliptical with rounded ends, and the radius of the body portion of the tank being less than half the length of the terminal bushing.

20. The combination in a liquid-break circuit interrupter of a tank having a body portion of generally circular shape when viewed in side elevation, 21 pair of termrnal bushings converging inwardly and extending into the body portion of the tank from the upper end thereof, upwardly extending housing means at the top of the body portion of the tank and supporting each of the terminal bushings adjacent the mid-portion thereof, horizontal sectlons taken through the body portion of the tank being generally elliptical with rounded ends, and the radius of the body portion of the tank being less than half the length of the terminal bushing.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 188,245 Horsford Mar. 13, 1877 416,355 Chalk Dec. 3, 1889 655,979 Lanz Aug. 14, 1900 1,156,542 Merriam Oct. 12, 1915 1,394,951 Sugimura Oct. 25, 1921 1,401,988 Knapp -1 Jan. 3, 1922 1,755,068 MacDonald Apr. 15, 1930 1,907,827 Kelle May 9, 1933 1,957,983 Smith May 8, 1934 1,957,985 Smith May 8, 1934 2,111,954 Urbany Mar. 22, 1938 2,180,561 Stevens Nov. 21, 1939 FOREIGN PATENTS Number Country Date 626,198 Great Britain July 11, 1949 

